Connector fitting for externally insulated conduits



April 1966 A. l. APPLETON 3,245,700

CONNECTOR FITTING FOR EXTERNALLY INSULATED CONDUITS Filed Feb. 2'7, 1963AIYA' If??? 25 za INVENTOR.

1 I 5- /rM/w $21 2 0,

United States Patent v 1 3,245,700 t CONNECTOR FITTING FOR EXTERNALLYINSULATED CONDUITS Arthur I. Appleton, Northbrook, Ill. AppletonElectric Co., '1713 Wellington Ave., Chicago 13, Ill.) Filed Feb. 27,1963, Ser. No. 261,465 1 Claim. (Cl. 285-149) The present inventionrelates generally to conduit connectors, and-more particularly, to anovel connector fitting for use with shielded electrical cables,conduits or the like which have an external covering of insulatingmaterial.

In recent years there has been a rapid growth in production .and'use ofexternally insulated conduits, shielded electrical cables and similardevices. Typically, such cables and conduits are insulated with auniform covering of rubber or plastic material such as neoprene. Thistype of material not only provides electrical insulation forthese-special cables'and conduits, but also protects the metallicportion of the cable or conduit from corrosive action due to moisture,gases, and other materials.

:Previously, when such externally insulated conduits have been coupledto a junction box or other connecting device, it has been necessary touse conventional type connectors which are not especially adapted foruse with this improved conduit. One connector which has been found'to beparticularly popular for this purpose is the type disclosed in mycopending application Serial No. 739,618, filed June 3, 1958. However,with this type connector it has not been possible to afford a strongsealing connection. between the connector and both the conduit and itsinsulated covering. Thus, it has been necessary to strip the insulationaway from the end ofthe conduit to which the connector is attached, andfrequently this leaves an exposed portion of the bare conduit adjacentthe connector. :Furthermore, there is often a tendency for theinsulating covering to work back from the connector and thus leaveanadditional portion of the bare conduit unprotected. In either of thesesituations, the conduit is particularly vulnerable to corrosive moistureand gases or other substances which tend to collect on the conduitadjacent the connector. The present invention, which is an improvementin connectors of the type covered in my above mentioned application, is,accordingly, intended to obviate the foregoing difiiculties.

--It is the primary aim of the present invention to provide aconnectorfitting for externally insulated conduits or the like which isconstructed to firmly grip'and seal both the conduit and the insulatedcovering to the connector.

A more particular object is to provide such a connector with individualsealing elements which respectively grip the :conduit and the insulatedcovering and which are complementarily coupled to the connector inganged relation.

Anotherobject is to provide a connector of the above type in which theintermediate sealingelement operates to urge the connector into grippingengagement with the conduit and also forms the gripping element which isurged into sealing relation with the insulated covering.

It is a further object to provide a novel connector that is particularlyeconomical to manufacture and readily adapted for mass production inthat it comprises only three parts that may be simplyformed using commontools and methods.

Other objects and advantages of the invention will become more readilyapparent'upon reading the attached detailed description and uponreference to the drawings,

in-which:

'FIG. 1 is an exploded view of the parts of a connector embodying thepresent invention together with a section of an insulated conduit or thelike;

FIG. 2 is a fragmentary sectional view of the connector 3,245,730Patented Apr. 12, 1966 shown in FIG. 1 in position on the end of aninsulated conduit prior to being tightened and secured;

FIG. 3 is a View similar to FIG. 2 showing the parts in an intermediateposition with one element fully tightened; and

FIG. 4 is an elevational view partially in section, of the connectorshown in FIG. 1, fully tightened and secured on the end of an insulatedconduit.

While the invention will be described in connection with a preferredembodiment, it will be understood that I do not intend to limit theinvention to that embodiment. On the contrary, I intend to cover allalternatives, modifications and equivalents as may be included withinthe spirit and scope of the invention as defined by the appended claim.

Turning first to FIGURE 1, there is shown an illustrative connector 10embodying the present invention, comprising a threaded fitting member11, a first sealingele ment or nut 12 and a second sealing element ornut 13, positioned for connection to an electrical shield or conduit 14having a covering 15 of insulating material. When attached, theconnector 10 becomes a rigid and substantially integral part sealing andgripping both the conduit 14 and covering 15 and thereby permitting theinsulated conduit to be threadedly secured to a connection box orsimilar structure. 7

In regard to the illustrative fitting member 11, reference may be madeto my above mentioned copending application Serial No. 739,618, whichdescribes in detail the construction and function of such a fittingmember. However, the following brief description of the fitting willprovide an ample understanding for the purpose of the present invention.Referring more particularly to FIGS. 2-4, it

can be seen that the fitting 11 is a single, integral, annular memberhaving a main central bore 16' of a diameter to closely, but slidably,surround the particular conduit outer diameter with which the connector10 is intended to be utilized. A ridge 17 at one end of the bore 16provides a stop for accurately positioning the fitting 11 over the endof the conduit 14. The. fitting 11 also includes a nut portion 18 whichseparates a pipe threaded portion 19- for attachment to a connecting box(not shown) and an externally threaded portion 20 for threadablyreceiving an internally threaded portion 21 of the first sealing nut 12.

In accordance with the present invention, the fitting member 11 andfirst and second sealing nuts 12, 13 are so constructed that a strongsealing connection is afforded between the connector 10 and both thebare end of the conduit 14 and its insulated covering 15. For thispurpose, the fitting member 11 and the first sealing nut 12 are eachformed with respective thin-walled deformable portions 22 and 23 whichare individually urged into gripping contact about the exposed conduit14 and insulated covering 15 by internal cam portions 24 and 25 of therespectivesealing nuts 12, 13. Thus, threadably drawing the first andsecond sealing nuts respectively onto the fitting 11 and first nut 12,causes the cam portions 24, 25 on the nuts to inwardly deflect therespective deformable portions 22, 23 into sealing engagement with theconduit 14 which has been inserted into the fitting and with thecovering 15 whichhas been inserted into the first sealing nut.

To facilitate the sealing connection between the connector 10 and theconduit 14 and its insulated covering 15, the first sealing nut 12 isformed with a bore 26, similar in diameter to the bore'16 of the fitting11, so as to closely, but slidably, receive the diameter of the conduit14 and an enlarged counterbore 27, for closely, but slidably, receivingthe' enlarged diameter of the cylindrical covering 15. The bore 27terminates at its inward end by a'shoulder 28 which provides a stop foraccurately positioning the first sealing nut 12 against the insulatedcovering 15. An externally threaded portion 30 on the first sealing nut12 surrounds the enlarged bore 27 and is adapted to threadably receivean internally threaded portion 31 of the second sealing nut 13.

Referring now to the second sealing nut 13, it is provided with anaxially extending nose 32 having a smooth bore 33, approximately thesame diameter as the enlarged bore 27 of the first sealing nut 12, forclosely, but slidably, surrounding theinsulated covering 15. At itsouter end, the bore 33 is flared outwardly to define a rounded throat 34which eliminates the danger of having a sharp edge on the sealing nut 13dig into the insulation 15 when the latter is flexed relative to theconnector 10.

The function of the individual parts can best be seen by brieflydescribing the operational steps involved in the preferred procedure forinstalling the connector on the, insulated conduit 14.

The first and second sealing nuts 12, 13 are each loosely threaded onthe fitting body 11 and the first sealing nut 12 with the respective camportions 24, 25 lightly engaging the deformable portions 22, 23. Thiscouples the connector 10 together as an integral unit ready for reception of the conduit 14. At this time the fitting body may also besecured to a connection box or the like. The con-. duit 14 is theninserted into the bore 16 with the covering 15 entering the enlargedbore 27 until it strikes the shoulder .28 (-see FIG. 2). In thisposition, it maybe seen that the enlarged bore 27 of the second sealingnut 13 closely, but slidably surrounds the outer diameterof the covering15 and the bore 16 of the first sealing nut closely, but slidablysurrounds the diameter of the conduit 14.

By engaging the mating threads 20,. 21, the first sealing nut 12 is thenthreadably drawn onto the fitting member 11. As the nut 12 is rotatedalong the fitting 11, the cam portion 24 strikes the deformable portion22, deflecting it inwardly with a turning action, so as to grippinglyseal the body 11 with the ,cylindrical portion of the conduit 14.Similarly, the mating threads 30, 31 are then engaged and the secondsealing nut 13 is threadably drawn onto the first sealing nut 12. Incorresponding fashion, as the nut 13 is rotated along. the nut 12, thecam portion 25 strikes the deformable portion 23, deflecting it inwardlywith a turning action, so as to sealingly grip the insulated covering.

In following the above procedure it will also be seen that by firsttightening the first sealing nut 12, to urge the deformable portion 22into gripping relation with the conduit 14, the second sealing nut 13 isfreely slid along the covering 15 without scuffin'g or marring theprotective covering. On the other hand, if. the secondnut 13 istightened first, considerable scuflingof either the conduit 14 orcovering 15 or both results. Therefore, to facilitate the preferredprocedure and to insure that an adequate sealing engagement is affordedwith both the conduit 14 and covering 15, the axial dimension of theenlarged bore 27 of the first sealing nut is greater than the axialdimen, sion of the cam portion 24. Thus, when the cam portion 24 isfully engaged .with the deformable portion 22, the enlarged bore 26 andits attached deformable portion 23 r are still positioned well over theinsulated covering 15.

It will be noted as a feature of the invention embodied in the connector10 that when the connector is installed, on the end of the insulatedcable, the conduit or the like .is not only rigidly supported by thebiting engagement of the connector, but also, the connector entirelycovers the exposed portion of the conduit 14 and sealingly grips theinsulating covering to the connector. The importance of this feature canbe more fully appreciated, bearing in mind the conduit 14 has arelatively thin wall and that moisture and corrosive substances mostfrequently accumulate on the conduit adjacent such a connector. How--ever, in the present instance, since the connector 10 entirely coversthe bare conduit 14 and sealin'gly engages the covering 15, thepossibility of holes forming inthe conduit 14 is substantiallyminimized. Moreover, with the covering 15 firmly gripped by theconnector 10, the tendency of the covering to peel away from conduit 14is also diminished.

It will also be appreciated that when installing the connector 10,neither the conduit 14 nor the fitting member 11 need be rotated sincethe. entire connecting operation can be performed by rotating the twosealing nuts 12, 13 relative to both the conduit 14 and the fittingmember 11. Thus, if it is desired to secure the end of the conduit 14 toa connection box or the like, the fitting 11 can first be threadablyinstalled in the connection box before-being secured to the conduit.Once the fitting member 11 has been properly positioned, the conduit 14can then be slid into the bore 16 and the sealing nuts 12, 13,respectively, rotated to lock the assembly into the desired position.

The connector. 10 embodying the present invention is also quite'sim-pleand economical to manufacture since only three pieces are .required andeach of these are readily adapted for mass production with ordinarymachine tools. Moreover, it is important to note that the connector 10may be readily formed from light, easily shaped materials, such asaluminum.

I claim as my invention:

A connector fitting intended for attachment to a conduit or the likehaving an exposedcylindrical end with an enlarged cylindrical coveringadjacent thereto of greater outside diameter, comprising, a fitting bodyhaving a first central bore for closely'but slidably receiving saidexposed end and having an externally threaded portion, a first sealingnut adapted .to rotatably engage said threaded body portion and having asecond central bore of substantially the same diameter as said firstcentral bore and extending entirely therethrough, said first sealing nuthaving an enlarged counterbore coaxial with said second central bore andextending partially therethrough for closely but slidably receiving saidenlarged cylindrical covering, said first sealing nut havinganexternally threaded portion surrounding said second central bore andsaid counterbore, a second sealing nut adapted to rotatably engage saidexternally threaded nut portion, said body and said first sealing nuteach having a deformable thin-walled portion extending axially beyondsaid respective externally threaded portion, said .counterbore of saidfirst sealing nut joining said second centralbore by means of asubstantially radial shoulder to form a stop to be engaged by the end ofsaid cylindrical covering to limit axial insertion of said conduit intosaid first nut, and said first and second sealing nuts each formed withan internal cam portion so that as said sealing nuts are respectivelythreaded in sequence onto said fitting body and first sealing nut, saiddeformable body portion is first urged into gripping engagement aboutsaid exposed conduit end and said deformable nut portion is then urgedinto gripping engagement about said enlarged cylindrical covering, theaxial dimension of said counterbore being greater than the axialdimension of said cam portion of saidfirst sealing nut so that when.said cam portion of said sealing nut is fully engaged with saiddeformable body portion, the wall of said counterbore still overliessaid covering whereby the deformable nut portion of said firstsealingnut will overlie said covering and be deformed into engagement therewithupon operation of said second sealing nut.

References Cited by the Examiner UNITED STATES PATENTS 1,904,617 4/1933Buchanan 285l69 2,268,263 12/1941 Newell 285l38 2,564,302 8/1951 Fraser1 285-449 2,858,358 10/1958 Hawke' 33927O 3,039,796 6/1962 Lawman285--382.7 X 3,079,182 2/1963 Appleton -1 285-382 CARL W. TOMLIN,Primary Examiner.

